John Travolta’s 16-year-old son, Jett, died yesterday after suffering a seizure and hitting his head on a bathtub while vacationing with his family in the Bahamas, police said.

The boy’s body was discovered by his caretaker, Jeff Kathrain, at around 10 a.m. in a bathtub in the Travoltas’ suite at the Old Bahama Bay Resort Hotel on Grand Bahama Island, local police chief superintendent Basil Rahming told The Post.

Attempts to revive Jett were not successful and he was pronounced dead on arrival at Rand Memorial Hospital, officials said.

“We are still investigating,” Rahming said.

Neither Travolta, wife Kelly Preston – on the island for a two-day New Year’s celebration – nor anyone else had seen the teen alive since he went to use the bathroom the prior evening, according to a police report.

Family members said they believe Jett died from a seizure, according to Travolta’s attorney, Michael Ossi.

Jett had a long history of seizures and other medical problems, including complications resulting from Kawasaki disease, a rare lymph-node disorder that causes severe rashes and fevers, Travolta told investigators.

Authorities will conduct an autopsy to determine the exact cause of death.

But those who have seen Jett in public, most recently in Paris two months ago, speculate the boy was autistic.

Some contend that Travolta – who never talked publicly about Jett – refuses to acknowledge the condition because of his belief in Scientology, which frowns upon mental illness and rejects psychology and psychiatry.

“There was unspoken communication between the two . . . It’s just so hard,” family friend Michael McDermott said. “Kelly is very quiet and both are grieving.”

Preston went on the “Montel Williams Show” in 2002 to talk about Kawasaki disease, which she said Jett developed as a result of inhaling household chemicals.

The disease tends to afflict young children, predominantly in Asia. Jett was put on a special detox program as prescribed by Scientology, Preston said.

“He ended up getting better,” she said, but noted the boy still “has lots of allergies.” In 2007, one of Travolta’s Florida neighbors, whose son is autistic, said he was shocked that the movie star could let his beliefs stand in the way of helping the boy.

“They see it as a weakness. That’s what the space aliens are telling him, I guess,” Tim Kenny told Hollywoodinterrupted.com after approaching Travolta as “one autistic father to another.”

“Scientology is keeping him from acknowledging his son’s autism. They see it as a weakness,” he said.

Kenny also complained that unlike other celebrity fathers of autistic children, such as Sylvester Stallone, Travolta has done nothing to help.

In the world according to L. Ron Hubbard, as Tom Cruise has pointed out to much criticism, Western medicine and antidepressants are frowned upon. Instead, a cure of hard work is preferred. The existence of autism is not acknowledged.

Travolta has reportedly bragged about Jett’s passion for reading and sports, but it was clear to observers that he barely was able to do either.

When the family was criticized for neglecting Jett’s condition, attorney Marty Singer called the charge “false and defamatory.”

“The Travoltas are wonderful, loving parents, and their priority is their children,” Singer told The Post at the time.

“They have [taken] and they continue to take the best possible care of their children.”

The family arrived in the Bahamas Tuesday on a private jet flown by Travolta.

Travolta, 54, Preston, 46, and 8-year-old daughter Ella Bleu will appear along with Robin Williams in the upcoming film “Old Dogs.”